Chrysothrix candelaris, commonly known as the gold dust lichen or egg yolk lichen, is a distinctive sorediate crustose lichen formed by the mutualistic association of a fungal partner (Chrysothrix candelaris, class Arthoniomycetes) with green algal photobionts. The lichen is immediately recognizable by its bright chrome-yellow to yellow-orange powdery soredia — granular reproductive propagules — which form a continuous farinose crust on the bark of acidic-barked trees, rock surfaces, and decaying wood in shaded, humid conditions. The vivid yellow color is due to calycin and other xanthone pigments. C. candelaris is widely distributed across Europe, North America, and South America, growing on smooth-barked deciduous and coniferous trees, boulders, and cliff faces in woodland and boreal forest habitats. It is assessed as Least Concern by the IUCN, reflecting its broad distribution and tolerance of a range of microhabitats. The lichen serves as a bioindicator of old-growth forest conditions and is sometimes used in air quality monitoring, as it is moderately sensitive to sulfur dioxide pollution. C. candelaris reproduces vegetatively through the dispersal of soredia by wind, water, and animals, which carry photobiont and mycobiont cells together.